Description

The Journal of Endodontics, the official journal of the American Association of Endodontists, publishes scientific articles, case reports and comparison studies evaluating materials and methods of pulp conservation and endodontic treatment. Endodontists and general dentists can learn about new concepts in root canal treatment and the latest advances in techniques and instrumentation in the one journal that helps them keep pace with rapid changes in this field. The Journal has an impact factor of 1.933, the highest of any journal in the specialty (2005 Journal Citation Index).

Publisher details

Elsevier

Publications in this journal

• The Effect of Surfactant Addition to EDTA on Microhardness of Root Dentin

  Authors: Ilgın Akcay, Bilge H. Sen

  Journal of Endodontics.

  Introduction The aim of this study was to investigate the effect of different concentrations of cetrimide with or without 5% EDTA solution on the microhardness of human root dentin inIntroduction The aim of this study was to investigate the effect of different concentrations of cetrimide with or without 5% EDTA solution on the microhardness of human root dentin in vitro. Methods Twenty-five recently extracted single-rooted human teeth were selected. The roots were split longitudinally into 2 parts. The specimens were randomly divided into the following 5 groups and were treated with 5% EDTA, 5% EDTA + 0.25% cetrimide, 5% EDTA + 0.50% cetrimide, 0.25% cetrimide, and 0.50% cetrimide immediately after the initial baseline microhardness measurements. A standardized volume of 50 mL of each solution was used for 1 minute. The reference microhardness values of untreated specimens were initially measured with a Vickers indenter under a 50-g load and a 10-second dwell time at the midroot level of the root dentin. Post-treatment microhardness values were obtained in the same manner as the initial ones. The decrease in microhardness was calculated as a percentage. Data were analyzed statistically by 1-way analysis of variance (P = .05) and the post hoc Tukey test for multiple comparisons at the same level of significance. Results All solutions significantly decreased the microhardness of root dentin (P < .05). Although there was no significant difference among the solutions (P > .05), the specimens in the EDTA + 0.50% cetrimide solution group showed the highest change in microhardness. The plain EDTA and plain 0.50% cetrimide groups had similar values. Conclusions The use of surfactants higher than 0.25% in concentration is questionable for clinical conditions.

• Antagonistic irrigants between sodium hypochlorite, chlorhexidine, EDTA and citric acid

  Authors: G. Rossi-Fedele, E. J. Dogramaci, A. R. Guastalli, L. Steier, De Figueiredo, J. A. P.

  Journal of Endodontics.

• Barodontalgia.

  Authors: Yehuda Zadik

  Journal of endodontics. 35(4):481-5.

  Although considered rare, dentists may encounter oral pain evoked by a change in barometric pressure, a condition known as barodontalgia (aerodontalgia). The article reviews the epidemiology,Although considered rare, dentists may encounter oral pain evoked by a change in barometric pressure, a condition known as barodontalgia (aerodontalgia). The article reviews the epidemiology, clinical presentation, pathogenesis, diagnostic process and differential diagnosis (including facial and dental barotrauma) of this phenomenon. Preventive measures are described as well.

• Histologic investigation of root canal-treated teeth with apical periodontitis: a retrospective study from twenty-four patients.

  Authors: Domenico Ricucci, José F Siqueira, Anna L Bate, Thomas R Pitt Ford

  Journal of endodontics. 35(4):493-502.

  This study intended to examine histologically root canal-treated teeth evincing apical periodontitis lesions and correlate the findings with clinical observations. Specimens were obtained from 24This study intended to examine histologically root canal-treated teeth evincing apical periodontitis lesions and correlate the findings with clinical observations. Specimens were obtained from 24 patients (12 asymptomatic and 12 symptomatic) by extraction or endodontic surgery and consisted of roots or root tips and the associated pathologic lesion. Specimens were processed for histologic analysis, and serial sections were evaluated. Findings were correlated with clinical observations according to the presence or absence of symptoms. The mean period elapsed from treatment to specimen retrieval in the asymptomatic group was 7.5 years, as compared with 2.2 years in the symptomatic group. All specimens exhibited periradicular inflammation. Bacteria were visualized in all cases, except for 1 specimen from the asymptomatic group in which a foreign body reaction to overfilled material was the probable reason for emergent disease in a previously vital case. Irrespective of the presence of symptoms, bacteria were always located within the root canal system, although they were also observed in the periradicular tissues in 1 asymptomatic and 4 symptomatic teeth. In general, intraradicular bacterial colonization was heavier in symptomatic failed teeth. The present findings support the role of intraradicular infections, usually in the form of biofilms, as the primary cause of endodontic treatment failure.

• Prostaglandin F(2alpha)-induced interleukin-8 production in human dental pulp cells is associated with MEK/ERK signaling.

  Authors: Mei-Chi Chang, Hsiao-Hua Chang, Mon-Ying Lee, Chiu-Chun Lin, Hung-Wei Yeh, Ting-Ting Yang, Po-Shuen Lin, Wan-Yu Tseng, Jiiang-Huei Jeng

  Journal of endodontics. 35(4):508-12.

  Prostaglandin F(2alpha) (PGF(2alpha)) and interleukin-1beta (IL-1beta) levels are elevated in inflamed dental pulp. The roles of IL-1beta and PGF(2alpha) in the pathogenesis of pulpal inflammationProstaglandin F(2alpha) (PGF(2alpha)) and interleukin-1beta (IL-1beta) levels are elevated in inflamed dental pulp. The roles of IL-1beta and PGF(2alpha) in the pathogenesis of pulpal inflammation await investigation. We found that IL-1beta stimulated PGF(2alpha) production of human dental pulp cells. IL-1beta and PGF(2alpha) (0.5-10 mumol/L) also induced IL-8 production and mRNA expression in pulp cells. Aspirin inhibited IL-1beta-induced PGF(2alpha), but not IL-8 production. PGF(2alpha)-induced IL-8 production and mRNA expression were inhibited by U0126 (an inhibitor of mitogen-activated protein kinase kinase [MEK1/2]) inhibitor), whereas SQ22536 (an adenylate cyclase inhibitor) enhanced this event. These results indicate that IL-1beta-induced IL-8 production in pulp cells is not mainly via direct activation of cyclooxygenase and PGF(2alpha) generation. PGF(2alpha)-induced IL-8 production is possibly via activation of MEK/extracellular signal-regulated kinase signaling, but not by activation of adenylate cyclase. IL-1beta and PGF(2alpha) might involve the pathogenesis of pulpal inflammation via induction of IL-8 production.

• Gene expression of human beta-defensins in healthy and inflamed human dental pulps.

  Authors: Sebastian Paris, Michael Wolgin, Andrej Michael Kielbassa, Axel Pries, Andreas Zakrzewicz

  Journal of endodontics. 35(4):520-3.

  Human beta-defensins (hBDs) are antimicrobial peptides that play an important role in the innate host defense against bacterial invasion, contribute to promotion of adaptive immune responses, andHuman beta-defensins (hBDs) are antimicrobial peptides that play an important role in the innate host defense against bacterial invasion, contribute to promotion of adaptive immune responses, and show chemotactic activities. The aim of this study was to compare the gene expression of hBD-1, -2, -3, and -4 in healthy teeth and teeth with pulpitis. Samples of healthy and inflamed dental pulps were obtained from extracted third molars and during treatment of teeth with pulpitis. Gene expression was assessed by using reverse transcriptase reaction and real-time polymerase chain reaction. HBD-2 and hBD -3 were only weakly expressed in healthy and inflamed pulps. In contrast, the expression of hBD-1 and hBD -4 was significantly increased in inflamed compared with healthy pulps. These results suggest that hBD-1 and hBD-4 might play a role in the pulpal host defense.

• Cholinoceptor modulation on nitric oxide regulates prostaglandin E(2) and metalloproteinase-3 production in experimentally induced inflammation of rat dental pulp.

  Authors: Alejandra De Couto Pita, Enri Borda, Sabrina Ganzinelli, Daniela Passafaro, Leonor Sterin-Borda

  Journal of endodontics. 35(4):529-36.

  The purpose of this study was to investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of inducible nitric oxide synthase (iNOS) activity, prostaglandin E(2)The purpose of this study was to investigate the role of muscarinic acetylcholine receptor (mAChR) activity in the regulation of inducible nitric oxide synthase (iNOS) activity, prostaglandin E(2) (PGE(2)), and metalloproteinase-3 (MMP-3) in experimentally induced inflammation of rat incisors dental pulp. Inflammation was induced by application of bacterial lipopolysaccharide (LPS) to the pulp. Extirpated pulp tissue samples were incubated in saline solution until the various experiments were performed. Saline-treated pulp and healthy pulp were used as controls. NOS activity was measured by the production of [U-(14)C]-citrulline from [U-(14)C]-arginine. PGE(2) and MMP-3 production were evaluated by an enzyme-linked immunosorbent assay (ELISA) and cyclooxygenase (cox-1 and cox-2) messenger RNA levels were measured using a reverse-transcriptase polymerase chain reaction by coamplification of target complementary DNA with a single set of primers. The application of LPS to the pulp increased NOS activity, PGE(2), and MMP-3 production associated with iNOS overactivity. Moreover, PGE(2) and MMP-3 production were the result of cox-2 expression. Pilocarpine (5 x 10(-11) mol/L to 5 x 10(-9) mol/L), acting on mAChRs, triggered a negative effect on NOS activity, PGE(2), and MMP-3 production. In control pulp, no action of pilocarpine was observed. Pulpitis changed mAChR conformation, increasing its coupling efficiency to transducing molecules that in turn activate iNOS. The capacity of pilocarpine to prevent iNOS activity, PGE(2), and MMP-3 by acting on mAChR mutation induced by pulpitis might be useful therapeutically as a local treatment.

• Evaluation of root canal obturation: a three-dimensional in vitro study.

  Authors: Mohammad Hammad, Alison Qualtrough, Nick Silikas

  Journal of endodontics. 35(4):541-4.

  The aim of the study was to measure percentage of volume of voids and gaps in root canals obturated with different obturation materials by using micro-computed tomography (micro-CT). Forty-eightThe aim of the study was to measure percentage of volume of voids and gaps in root canals obturated with different obturation materials by using micro-computed tomography (micro-CT). Forty-eight single-rooted teeth were collected and decoronated, and root canals were prepared by using rotary files. The roots were randomly allocated into 4 groups, and each group was obturated by using cold lateral compaction with a different material (gutta-percha and TubliSeal sealer, EndoRez points and EndoRez sealer, RealSeal points and RealSeal sealer, and a gutta-percha point and GuttaFlow sealer). Roots were scanned with micro-CT, and volume measurements for voids and gaps in the obturated roots were carried out by using specialized CT software. Percentage of gaps and voids was calculated. Statistical analysis showed that gutta-percha exhibited an overall significantly lower percentage (1.02%) of voids and gaps. The present study showed that none of the root canal filled teeth were gap-free. Roots filled with gutta-percha showed less voids and gaps than roots filled with the remaining filling materials.

• The influence of calcium chloride on the setting time, solubility, disintegration, and pH of mineral trioxide aggregate and white Portland cement with a radiopacifier.

  Authors: Eduardo Antunes Bortoluzzi, Norberto Juárez Broon, Clovis Monteiro Bramante, Wilson Tadeu Felippe, Mario Tanomaru-Filho, Roberto Miranda Esberard

  Journal of endodontics. 35(4):550-4.

  This study evaluated the influence of addition of 10% calcium chloride (CaCl(2)) on the setting time, solubility, disintegration, and pH of white MTA (WMTA) and white Portland cement (WPC). A test ofThis study evaluated the influence of addition of 10% calcium chloride (CaCl(2)) on the setting time, solubility, disintegration, and pH of white MTA (WMTA) and white Portland cement (WPC). A test of the setting time was performed following the #57 ADA specifications and a test of the final setting time according to the ASTM. For the solubility tests disintegration and pH, Teflon rings were filled with the cements and weighed after setting. After 24 h in a desiccator, they were once again weighed. Thereafter, they were immersed in MiliQ water for 24 and 72 h and 7, 14, and 28 days, with maintenance in the desiccator and weighing between periods. The pH of water in which the rings were immersed was measured immediately after contact with them and in the other periods. The addition of CaCl(2) provided a significant reduction (50%) in the initial setting time of cements. The final setting time of WMTA was reduced in 35.5% and the final setting time of WPC in 68.5%. The WMTA with CaCl(2) absorbed water and gained weight with time, except for in the 24-h period. The addition of CaCl(2) to the WPC reduced its solubility. The addition of CaCl(2) increased the pH of WMTA in the immediate period and at 24 and 72 h and for WPC in the immediate period and at 24 h. The addition of CaCl(2) to WMTA and WPC reduced the setting times and solubility of both and increased the pH of cements in the initial periods.

• Evaluating two techniques on removal of fractured rotary nickel-titanium endodontic instruments from root canals: an in vitro study.

  Authors: Khalid H Alomairy

  Journal of endodontics. 35(4):559-62.

  This study evaluated the ultrasonic technique (US) and instrument removal system (iRS) in removing fractured rotary nickel-titanium (NiTi) from root canals. A total of 30 extracted human molars withThis study evaluated the ultrasonic technique (US) and instrument removal system (iRS) in removing fractured rotary nickel-titanium (NiTi) from root canals. A total of 30 extracted human molars with closed apices were collected. Profile .06 taper rotary endodontic instruments (Dentsply Maillefer, Ballaigues, Switzerland) 25-mm long and ISO size 25 were driven into the mesial canal to be fractured in the curve. Angles and radii of curvature were measured for all the canals with the fractured fragments, and then canals were classified into slight, moderate, and severe subgroups according to their curvature angles. Within each subgroup, teeth were randomly distributed into US or iRS according to measured angles and radii; a total of 15 canals were assigned to both US and iRS techniques. The overall success rate was 70% (n = 21). Less curved canals and longer radii of curvature showed more success. The median time used for retrieval was 40 minutes using the US technique, whereas it was 55 minutes for iRS. The removal of fractured rotary NiTi endodontic instruments was more successful with less curved canals and longer radius of curvature above 4.4 mm.

• A novel platform for in vitro analysis of torque, forces, and three-dimensional file displacements during root canal preparations: application to ProTaper rotary files.

  Authors: Amadou Diop, Nathalie Maurel, Michel Oiknine, Etienne Patoor, Pierre Machtou

  Journal of endodontics. 35(4):568-72.

  We proposed a new testing setup and in vitro experimental procedure allowing the analysis of the forces, torque, and file displacements during the preparation of root canals using nickel-titaniumWe proposed a new testing setup and in vitro experimental procedure allowing the analysis of the forces, torque, and file displacements during the preparation of root canals using nickel-titanium rotary endodontic files. We applied it to the preparation of 20 fresh frozen cadaveric teeth using ProTaper files (Dentsply Maillefer, Ballaigues, Switzerland), according to a clinically used sequence. During the preparations, a clinical hand motion was performed by an endodontist, and we measured the applied torque around the file axis and also the involved three-dimensional forces and 3-dimensional file displacements. Such a biomechanical procedure is useful to better understand the working conditions of the files in terms of loads and displacements. It could be used to analyze the effects of various mechanical and geometric parameters on the files' behavior and to get data for modelling purposes. Finally, it could contribute to studies aiming to improve files design in order to reduce the risks of file fractures.

• Bonding of self-adhesive (self-etching) root canal sealers to radicular dentin.

  Authors: Brian R Babb, Robert J Loushine, Thomas E Bryan, Jason M Ames, Mark S Causey, Jongryul Kim, Young Kyung Kim, R Norman Weller, David H Pashley, Franklin R Tay

  Journal of endodontics. 35(4):578-82.

  The latest generation of methacrylate resin-based sealers has eliminated the use of separate self-etching primers by incorporating acidic resin monomers in the sealers to render them self-adhesive toThe latest generation of methacrylate resin-based sealers has eliminated the use of separate self-etching primers by incorporating acidic resin monomers in the sealers to render them self-adhesive to dentin. This study examined the adhesive strengths, interfacial ultrastructure, and tracer penetration of a nonetching (EndoREZ; Ultradent, South Jordan, UT) and two self-adhesive methacrylate resin-based sealers (MetaSEAL; Parkell, Farmington, NY, and RealSeal SE; SybronEndo, Orange, CA) when they were applied to radicular dentin following the manufacturers' recommended use of EDTA as the active final rinse. A modified push-out testing design was used to evaluate the dislodgement of core-free sealers. The mixed sealers were placed in dimensionally identical, artificially created canal spaces prepared in the coronal, middle, and apical thirds of radicular dentin. After setting, each sealer-filled cavity was subjected to compressive loading until failure. Additional specimens were prepared for transmission electron microscopy to examine the ultrastructure and nanoleakage within the sealer-radicular dentin interface. The two self-adhesive sealers MetaSEAL and RealSeal SE exhibited higher push-out strengths than the nonetching sealer EndoREZ when EDTA was used as the active final rinse. All three sealers showed a 1- to 1.5-microm thick zone of partially demineralized dentin, with the EDTA dentin demineralization effect masking the true self-etching potential of MetaSEAL and RealSeal SE. The true self-etching potential of self-adhesive sealers is a clinically important attribute that should be further investigated. Incomplete smear layer removal from the apical third of instrumented canal walls may jeopardize the performance of self-adhesive sealers should they fail to self-etch without the adjunctive use of calcium chelating irrigants.

• Tooth bleaching with nonthermal atmospheric pressure plasma.

  Authors: Hyun Woo Lee, Gon Jun Kim, Jae Moon Kim, Jeong Kil Park, Jae Koo Lee, Gyoo Cheon Kim

  Journal of endodontics. 35(4):587-91.

  We demonstrated that room temperature plasma could be used for tooth bleaching. A nonthermal, atmospheric pressure, helium plasma jet device was developed to enhance the tooth bleaching effect ofWe demonstrated that room temperature plasma could be used for tooth bleaching. A nonthermal, atmospheric pressure, helium plasma jet device was developed to enhance the tooth bleaching effect of hydrogen peroxide (H(2)O(2)). All teeth were sectioned sagittally into halves, which were assigned randomly to either the experimental group or the control group. The experimental group was treated with H(2)O(2) (28%, 20 microL every 30 seconds) plus plasma (5 W) for 10 minutes; the control group was treated with H(2)O(2) alone for the same duration. Removal of the tooth surface protein was demonstrated by scanning electron microscopy images and Ponceau staining. Production of hydroxyl radicals (.OH) was measured by using electron spin resonance spin-trapping. Combining plasma and H(2)O(2) improved the bleaching efficacy by a factor of 3 compared with using H(2)O(2) alone. Tooth surface proteins were noticeably removed by plasma treatment. When a piece of tooth was added to a solution of H(2)O(2) as a catalyst, production of *OH after plasma treatment was 1.9 times greater than when using H(2)O(2) alone. We suggest that the improvement in tooth bleaching induced by plasma is due to the removal of tooth surface proteins and to increased *OH production.

• Calcium hydroxide-based root canal sealers: a review.

  Authors: Shalin Desai, Nicholas Chandler

  Journal of endodontics. 35(4):475-80.

  The aim of this review was to consider laboratory experiments and clinical studies of calcium hydroxide-based root canal sealers. An extensive search of the endodontic literature was made to identifyThe aim of this review was to consider laboratory experiments and clinical studies of calcium hydroxide-based root canal sealers. An extensive search of the endodontic literature was made to identify publications related to calcium hydroxide-based root canal sealers. The articles were assessed for the outcome of laboratory and clinical studies on their biological properties and physical characteristics. Comparative studies with other sealers were also considered. Several studies were evaluated covering different properties of calcium hydroxide-based sealers including physical properties, biocompatibility, leakage, adhesion, solubility, antibacterial properties, and periapical healing effect. Calcium hydroxide-based root canal sealers have a variety of physical and biological properties. Comparative studies reveal their mild cytotoxicity, but their antibacterial effects are variable. Further research is required to establish the tissue healing properties of calcium hydroxide in root canal sealers.

• Bacterial community profiling of cryogenically ground samples from the apical and coronal root segments of teeth with apical periodontitis.

  Authors: Flávio R F Alves, José F Siqueira, Flávia L Carmo, Adriana L Santos, Raquel S Peixoto, Isabela N Rôças, Alexandre S Rosado

  Journal of endodontics. 35(4):486-92.

  Bacteria located at the apical part of infected root canals are arguably directly involved in the pathogenesis of apical periodontitis. This study was conducted to profile and further compare theBacteria located at the apical part of infected root canals are arguably directly involved in the pathogenesis of apical periodontitis. This study was conducted to profile and further compare the bacterial communities established at the apical and middle/coronal segments of infected root canals. Extracted teeth with attached apical periodontitis lesions were sectioned so as to obtain two root fragments representing the apical third and the coronal two thirds. Root fragments were subjected to a cryogenic grinding approach. DNA was extracted from root powder samples and used as a template for bacterial community profiling using a 16S ribosomal RNA gene-based seminested polymerase chain reaction/denaturing gradient gel electrophoresis approach. The mean number of bands in apical samples from teeth with primary infections was 28, ranging from 18 to 48, whereas in the middle/coronal samples, it was also 28, ranging from 19 to 36. Findings showed that the profile of bacterial community colonizing the apical third of infected root canals is as diverse as that occurring at the middle/coronal thirds. A high variability was observed for both interindividual (samples from the same region but from different patients) and intraindividual (samples from different regions of the same tooth) comparisons. The methodology used to prepare and analyze samples was highly effective in disclosing a previously unanticipated broad diversity of endodontic bacterial communities, especially at the apical part of infected root canals.

• Detection of permanent three-rooted mandibular first molars by cone-beam computed tomography imaging in taiwanese individuals.

  Authors: Ming-Gene Tu, Heng-Li Huang, Shui-Sang Hsue, Jui-Ting Hsu, San-Yue Chen, Ming-Jia Jou, Chi-Cheng Tsai

  Journal of endodontics. 35(4):503-7.

  This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744This study determined the prevalence of permanent three-rooted mandibular first molars and their morphology among a Taiwanese population by using cone-beam computed tomography (CBCT). Images from 744 patients were screened to obtain 123 samples for this study. All permanent mandibular first molars were evaluated in axial sections from the pulpal floor to the apices of the roots to determine the number of roots. The interorifice distances from the distolingual (DL) canal to the mesiobuccal (MB) and distobuccal (DB) canals were also estimated. The prevalence of permanent three-rooted mandibular first molars was 33.33%, with a bilateral incidence of a symmetrical distribution of 53.65%. There was a significantly greater incidence of three-rooted teeth on the right side of the mandible than on the left, but gender did not show a significant relationship with this variant prevalence.The mean interorifice distances from the DL canal to the DB, MB, and ML canals of the permanent three-rooted mandibular molars were 2.7, 4.4, and 3.5 mm, respectively. The high prevalence of the DL root in permanent mandibular first molars among the Taiwanese (Chinese) population and estimations of the interorifice distance of such teeth might be useful for successful endodontic treatments.

• Effects of mineral trioxide aggregate on cell survival, gene expression associated with mineralized tissues, and biomineralization of cementoblasts.

  Authors: Sema S Hakki, S Buket Bozkurt, Erdogan E Hakki, Sema Belli

  Journal of endodontics. 35(4):513-9.

  The purpose of this study was to investigate the effects of mineral trioxide aggregate (MTA) on survival, mineralization, and expression of mineralization-related genes of cementoblasts. ImmortalizedThe purpose of this study was to investigate the effects of mineral trioxide aggregate (MTA) on survival, mineralization, and expression of mineralization-related genes of cementoblasts. Immortalized cementoblasts (OCCM) were maintained with Dulbecco modified Eagle medium containing 10% fetal bovine serum. Methyl-thiazol-diphenyl-tetrazolium experiments were performed at 24 and 72 hours to evaluate bioactive components released by MTA (0.002-20 mg/mL) on the cell survival of OCCM. Von Kossa staining was used to evaluate biomineralization of OCCM cells. Images of cementoblasts were taken on day 3 by using inverted microscopy. Gene transcripts for bone sialoprotein (BSP), OCN, collagen type I (COL I), and osteopontin (OPN) were evaluated on days 3 and 5 by using semiquantitative reverse transcriptase polymerase chain reaction. The 20 mg/mL concentration of MTA was toxic for OCCM cells, whereas other concentrations of MTA tested exhibited similar cell numbers when compared with control group, and the 0.02 mg/mL concentration of MTA increased OCCM cell survival at 72 hours. Although an apparent decrease in mineralization was observed in the highest 3 concentrations of MTA used, 0.02 and 0.002 mg/mL concentrations of MTA induced greater biomineralization of OCCM cells than seen in the control. Moreover, increased BSP and COL I mRNA expression was observed at 0.02 and 0.002 mg/mL concentrations of MTA. MTA did not have a negative effect on the viability and morphology of cementoblasts and induced biomineralization of cementoblasts at the concentrations of 0.02 and 0.002 mg/mL. Based on these results MTA can be considered as a favorable material regarding cell-material interaction.

• Anti-inflammatory effect of peroxisome proliferator activated receptor gamma on human dental pulp cells.

  Authors: Mi-Kyung Yu, Jung-Chang Lee, Jeong-Hee Kim, Young-Hee Lee, Jae-Gyu Jeon, Eun-Chung Jhee, Ho-Keun Yi

  Journal of endodontics. 35(4):524-8.

  Peroxisome proliferator activated receptor gamma (PPARgamma) plays a critical role in controlling immune and inflammatory responses. However, its effect on pulpal inflammation has not been clarified.Peroxisome proliferator activated receptor gamma (PPARgamma) plays a critical role in controlling immune and inflammatory responses. However, its effect on pulpal inflammation has not been clarified. The purpose of this study was to determine the anti-inflammatory effect of PPARgamma on pulpal inflammation. Human dental pulp cells treated with lipopolysaccharide exhibited elevated levels of matrix metalloproteinase-2 (MMP-2), MMP-9, intracellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). However, when treated with rosiglitazone (PPARgamma agonist) or adenoviral PPARgamma in same culture system, the expression of ICAM-1 and VCAM-1 was markedly inhibited along with decreased secretion of MMPs. In addition, the coadministration of GW9662 (PPARgamma antagonist) and rosiglitazone blocked the inhibition of MMP-2, MMP-9, ICAM-1, and VCAM-1. These results suggest that PPARgamma decreased the production of MMPs, ICAM-1, and VCAM-1 and might offer a possible attempt of using it as one of anti-inflammatory modulators in a pulpal inflammation.

• The effect of different irrigating solutions on bond strength of two root canal-filling systems.

  Authors: Ahmed Abdel Rahman Hashem, Angie G Ghoneim, Reem A Lutfy, Manar Y Fouda

  Journal of endodontics. 35(4):537-40.

  The bond strength of ActiV GP root canal filling system and gutta-percha/AH plus sealer when used after final rinse with different irrigation protocols was evaluated in this study. Forty roots wereThe bond strength of ActiV GP root canal filling system and gutta-percha/AH plus sealer when used after final rinse with different irrigation protocols was evaluated in this study. Forty roots were randomly divided into four groups (n = 10) according to the final irrigation regimen: group 1, 5 mL 17% EDTA; group 2, 5 mL 17% EDTA followed by 5 mL 2% chlorhexidine gluconate (CHX); group 3, 5 mL MTAD; and group 4, 5 mL MTAD followed by 5 mL 2% CHX. Each group was further subdivided into two subgroups (n = 5): in subgroup a, the root canals were filled using warm gutta-percha and AH plus sealer, and in subgroup b, the root canals were filled using the ActiV GP obturation system. Two-millimeter thick horizontal sections from the coronal and midthirds of each root were sliced for the push-out bond strength measurement. EDTA/CHX/ActiV GP (2.46 +/- 1.02 MPa) yielded significantly the highest mean bond strength value. The significantly lowest bond strength was recorded for EDTA/ActiV GP (1.12 +/- 0.72 MPa). It was concluded that the bond strength of ActiV GP was improved by using 2% CHX in the final irrigation after 17% EDTA, whereas CHX did not enhance the effect of MTAD on the bond strength of the material. The bond strength of gutta-percha/AH plus was adversely affected by MTAD and MTAD/CHX.

• Cyclic fatigue resistance of two variable-taper rotary file systems: ProTaper universal and V-Taper.

  Authors: Sterling J Whipple, Timothy C Kirkpatrick, Richard E Rutledge

  Journal of endodontics. 35(4):555-8.

  The cyclic fatigue resistance of ProTaper Universal (Dentsply Tulsa Dental Specialties, Tulsa, OK) and V-Taper (Guidance Endo, Albuquerque, NM) files was measured while rotating files around a 5-mmThe cyclic fatigue resistance of ProTaper Universal (Dentsply Tulsa Dental Specialties, Tulsa, OK) and V-Taper (Guidance Endo, Albuquerque, NM) files was measured while rotating files around a 5-mm radius curve with 90 degrees of maximum flexure. The files were rotated at 250 rpm with a continuous axial oscillation of 4 mm at 1 Hz. The number of cycles to failure was calculated and analyzed by using univariate analysis of variance and the Tukey HSD posthoc test with results confirmed by nonparametric Kruskal-Wallis and Mann-Whitney U tests with a Bonferroni correction. The fracture faces of representative files were imaged with a scanning electron microscope to confirm cyclic fatigue as the mode of fracture. For the instruments tested, the ProTaper files appeared to resist fracture better than the V-Taper files. At each tip size tested, the ProTaper files either outperformed or were not statistically different than V-Taper files.

• The efficacy of different sealer removal protocols on bonding of self-etching adhesives to AH plus-contaminated dentin.

  Authors: Steven Roberts, Jong Ryul Kim, Li-Sha Gu, Young Kyung Kim, Quinn M Mitchell, David H Pashley, Franklin R Tay

  Journal of endodontics. 35(4):563-7.

  INTRODUCTION: Smearing of unset root canal sealers over the pulp chamber dentin may adversely affect bonding of self-etching adhesives and jeopardize their coronal sealing potential. This studyINTRODUCTION: Smearing of unset root canal sealers over the pulp chamber dentin may adversely affect bonding of self-etching adhesives and jeopardize their coronal sealing potential. This study examined the influence of different sealer removal protocols on the microtensile bond strengths of two self-etching adhesives to AH Plus-contaminated dentin. METHODS: Coronal dentin surfaces were prepared from extracted human third molars. In the positive control groups, these surfaces were not contaminated with sealer and were bonded with Clearfil SE Bond or Clearfil Tri-S Bond. For the experimental groups, dentin surfaces were contaminated with AH Plus and wiped with either dry cotton pellets, cotton pellets saturated with ethanol, or cotton pellets saturated with Endosolv R followed by rinsing the dissolved sealer with water prior to bonding with the two adhesives. Bonded specimens were sectioned into resin-dentin beams for microtensile bond strength evaluation. Additional specimens were prepared for transmission electron microscopy to examine the ultrastructure and nanoleakage within the hybrid layers. RESULTS: For both adhesives, microtensile bond strengths significantly declined when the sealer was removed with dry cotton pellets or cotton pellets saturated with ethanol. Only the Endosolv R/water sealer removal protocol restored tensile bond strengths to those of the uncontaminated positive controls without adversely affecting hybrid layer formation in intact dentin or increasing nanoleakage within the resin-dentin interfaces. CONCLUSION: The Endosolv R sealer removal protocol appears to be effective in preventing the deterioration of bond strengths of the two self-etching adhesives to AH Plus-contaminated dentin and warrants further clinical investigation.

• Effect of different irrigation on smear layer removal after post space preparation.

  Authors: Xin-Hua Gu, Cai-Yun Mao, Matthias Kern

  Journal of endodontics. 35(4):583-6.

  The purpose of this study was to evaluate the effect of different irrigating solutions on smear layer removal and dentinal tubule opening on root canal surfaces after post space preparation and toThe purpose of this study was to evaluate the effect of different irrigating solutions on smear layer removal and dentinal tubule opening on root canal surfaces after post space preparation and to study whether additional ultrasonic irrigation has any effect on smear layer removal. Forty-eight anterior teeth were treated endodontically. After post space preparation, they were assigned to six groups: group 1, EDTA; group 2, EDTA with ultrasonic activation; group 3, sodium hypochlorite (NaOCl); group 4, NaOCl with ultrasonic activation; group 5, sodium chloride (NaCl); and group 6, NaCl with ultrasonic activation. Specimens were examined under a field-emission scanning electron microscope and scored for debris removal and dentinal tubule opening at the coronal, middle, and apical thirds of the root canal. The results showed that EDTA performed significantly better than NaCl and NaOCl in smear layer removal and dentinal tubule opening. Additional ultrasonic irrigation did not improve smear layer removal significantly.

• Pulse oximetry: review of a potential aid in endodontic diagnosis.

  Authors: Hamid Jafarzadeh, Paul A Rosenberg

  Journal of endodontics. 35(3):329-33.

  Tests relying on the passage of light through a tooth have been considered to be a suitable means of assessing vascularity and pulp vitality. Pulse oximetry is an effective, objective oxygenTests relying on the passage of light through a tooth have been considered to be a suitable means of assessing vascularity and pulp vitality. Pulse oximetry is an effective, objective oxygen saturation monitoring technique broadly used in medicine for recording blood oxygen saturation levels. It can also be used in endodontic diagnosis for differential diagnosis of vital pulps and necrotic ones. In pulse oximetry, light is passed from a photoelectric diode across the tooth structure into a receptor. The instrument detects changes in absorption in both red and infrared light caused by alteration in tissue volume (tissue perfusion) during the cardiac cycle. However, there are some limitations inherent in the technology of pulse oximetry, such as the effect of increased acidity and metabolic rate, which cause deoxygenating of hemoglobin and changes in the blood oxygen saturation. Also, movements of the body or probe can complicate readings. Because this test produces no noxious stimuli, apprehensive or distressed patients may accept it more readily than routine methods. A review of the literature and a discussion of the potential application of this system in endodontics are presented.

• Analysis of the internal anatomy of maxillary first molars by using different methods.

  Authors: Flares BARATTO FILHO, Suellen Zaitter, Gisele Aihara HARAGUSHIKU, Edson Alves de Campos, Allan Abuabara, Gisele Maria Correr

  Journal of endodontics. 35(3):337-42.

  The success of endodontic treatment depends on the identification of all root canals so that they can be cleaned, shaped, and obturated. This study investigated internal morphology of maxillary firstThe success of endodontic treatment depends on the identification of all root canals so that they can be cleaned, shaped, and obturated. This study investigated internal morphology of maxillary first molars by 3 different methods: ex vivo, clinical, and cone beam computed tomography (CBCT) analysis. In all these different methods, the number of additional root canals and their locations, the number of foramina, and the frequency of canals that could or could not be negotiated were recorded. In the ex vivo study, 140 extracted maxillary first molars were evaluated. After canals were accessed and detected by using an operating microscope, the teeth with significant anatomic variances were cleared. In the clinical analysis, the records of 291 patients who had undergone endodontic treatment in a dental school during a 2-year period were used. In the CBCT analysis, 54 maxillary first molars were evaluated. The ex vivo assessment results showed a fourth canal frequency in 67.14% of the teeth, besides a tooth with 7 root canals (0.72%). Additional root canals were located in the mesiobuccal root in 92.85% of the teeth (17.35% could not be negotiated), and when they were present, 65.30% exhibited 1 foramen. Clinical assessment showed that 53.26%, 0.35%, and 0.35% of the teeth exhibited 4, 5, and 6 root canals, respectively. Additional root canals were located in this assessment in mesiobuccal root in 95.63% (27.50% could not be negotiated), and when they were present, 59.38% exhibited 1 foramen. CBCT results showed 2, 4, and 5 root canals in 1.85%, 37.05%, and 1.85% of the teeth, respectively. When present, additional canals showed 1 foramen in 90.90% of the teeth studied. This study demonstrated that operating microscope and CBCT have been important for locating and identifying root canals, and CBCT can be used as a good method for initial identification of maxillary first molar internal morphology.

• Identification and Characterization of Clinically Isolated Biofilm-forming Gram-positive Rods from Teeth Associated with Persistent Apical Periodontitis.

  Authors: Kazuyoshi Yamane, Kan Ogawa, Masahiro Yoshida, Hiroyuki Hayashi, Toshio Nakamura, Takeshi Yamanaka, Toshio Tamaki, Hirokazu Hojoh, Kai-Poon Leung, Hisanori Fukushima

  Journal of endodontics. 35(3):347-52.

  We isolated spore-forming gram-positive aerobic rods from three patients with persistent periapical periodontitis. These cells possessed unique phenotypic characteristics by exhibiting denseWe isolated spore-forming gram-positive aerobic rods from three patients with persistent periapical periodontitis. These cells possessed unique phenotypic characteristics by exhibiting dense meshwork-like structures on their cell surfaces that could be found in a number of biofilm-forming bacteria. We identified these strains as Bacillus subtilis by the API system and 16S ribosomal RNA gene (rRNA) sequencing. Treatment of the meshwork-like structures with protease K and staining with calcofluor for polysaccharides indicated that these structures were polysaccharides in nature and could be essential for biofilm formation by these isolates. Our findings suggest that B. subtilis could form biofilms in periapical periodontitis lesions, and this might contribute to the resistance to treatment resulting in the development of persistent periapical periodontitis observed in these patients. The particular mechanisms for B. subtilis biofilms to develop periapical periodontitis are still unknown. Further studies are needed to clarify the role of biofilms in persistent infections.

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